JP4449879B2 - Anti-vibration bush - Google Patents

Description

  The present invention relates to an anti-vibration bush, and more particularly to a feature of technical means for improving durability.

Conventionally, an anti-vibration bush having a rigid inner cylinder member and an outer cylinder member and a rubber elastic body disposed therebetween has been widely used as a suspension bush or the like.
As an example of the vibration isolating bushing, the rubber elastic body is provided with a pair of straight portions penetrating the rubber elastic body in the axial direction at both sides in the direction perpendicular to the axis across the inner cylinder member. A pair of rubber main bodies configured to connect the inner cylinder member and the outer cylinder member in a direction perpendicular to the axis at a circumferential position between the two parts, and a pair of inner parts opposed to each other in the direction perpendicular to the axis with the straight part interposed therebetween 2. Description of the Related Art Conventionally, a rubber stopper portion on the cylinder member side and a rubber stopper portion on the outer cylinder member side are provided with the same rubber material in a continuous form.
FIG. 6 shows one specific example.

In the figure, reference numeral 200 denotes an inner cylinder fitting (rigid inner cylinder member) in the vibration isolating bush 202, 204 denotes an outer cylinder fitting (rigid outer cylinder member), and 206 denotes a rubber elastic body disposed between them. The tube fitting 200 and the outer tube fitting 204 are integrally vulcanized and bonded.
208 is a straight portion (recess) provided in the rubber elastic body 206, and is provided on both sides of the inner cylinder fitting 200 in the direction perpendicular to the axis.
These straight portions 208 are provided so as to penetrate the rubber elastic body 206 in the axial direction.

  Reference numeral 210 denotes a rubber main body configured to connect the inner tube fitting 200 and the outer tube fitting 204 in a direction perpendicular to the axis at a circumferential position between the raised portions 208 and 208, and 212 and 214 respectively sandwich the raised portion 208. A rubber stopper portion on the inner cylinder fitting 200 side and a rubber stopper portion on the outer cylinder fitting 204 side that are opposed to each other in the direction perpendicular to the axis, and a pair of each provided corresponding to the pair of curling portions 208.

  As described above, the inner cylinder fitting 200, the outer cylinder fitting 204, the pair of rubber main body portions 210, the pair of straight portions 208, and the rubber stopper portions 212 on the side of each pair of inner cylinder fittings 200, which connect them in the direction perpendicular to the axis. An anti-vibration bush 202 having a rubber elastic body 206 provided with a rubber stopper portion 214 on the outer cylinder fitting 204 side is disclosed in, for example, Patent Document 1 below.

In this type of anti-vibration bushing 202, a rubber material is first injected into the rubber main body 210 having the largest rubber volume at the time of vulcanization molding of the rubber elastic body 206, more specifically, into the molding cavity of the rubber main body 210, and then there. It is common sense to select the injection path of the rubber material in the mold and the position of the injection hole at its end so that the rubber material is rotated into the respective molding cavities of the rubber stoppers 212 and 214.
By doing so, it is considered that the injected rubber material can be uniformly filled in each molding cavity.
In this case, the injection hole rubber protrusion formed by the injection hole remains in the rubber body 210 after vulcanization molding.
216 in FIG. 6 represents the injection hole rubber protrusion.

By the way, the rubber main body 210 is a main part which absorbs vibration by elastic deformation when the vibration isolating bushing 202 is used and has a vibration isolating function, and there is an input in the twisting direction as shown in FIG. Strain and stress are always generated by F ₁ and the input F _{2 in the} direction perpendicular to the axis.
Thus, if the injection hole rubber protrusion 216 as described above remains standing on the rubber main body 210, the injection hole rubber protrusion 216 exists as if it were a foreign substance on the surface of the rubber main body 210. In particular, there is a problem that a large stress concentration is generated at the root portion, resulting in a crack at the root, which further progresses to cause a decrease in the durability life of the vibration isolating bush 202 as a whole.

JP 2000-88026 A

  The present invention has been made for the purpose of providing a vibration-proof bushing in which the durability life is not reduced by the presence of the injection hole rubber protrusion, against the background described above.

Thus, the present invention has a rigid inner cylinder member and outer cylinder member, and a rubber elastic body disposed between the inner cylinder member and the outer cylinder member. A pair of straight portions penetrating the rubber elastic body in the axial direction are provided on both sides in a direction perpendicular to the axis across the inner cylinder member, and at a circumferential position between the straight portion and the straight portion, A pair of rubber main body portions configured to connect the inner cylinder member and the outer cylinder member in the direction perpendicular to the axis, and a pair of rubber stoppers on the side of the inner cylinder member facing each other in the direction perpendicular to the axis with the straight portion interposed therebetween In the vibration-proof bushing in which the rubber stopper portion on the outer cylinder member side is provided in a continuous form with the same rubber material, the rubber material is disposed on the inner cylinder member side during vulcanization molding of the rubber elastic body. the rubber body portion and the injected into the molding cavity of the rubber stopper The injection path of the rubber material in the mold so as to turn the rubber material disposed on each of the forming cavity of the rubber stopper portion of the cylindrical member, the injection hole rubber protrusions formed at the injection hole of the end of the injection path the rubber body portion and without leaving the rubber stopper of the outer cylinder member, leaving the rubber stopper of the inner cylinder member, and the rubber stopper of the inner cylinder member side end surface in the axial direction, the outer It is separated from the axial end surface of the inner cylinder member to the axial center side at a larger interval than the interval between the axial end surface of the cylindrical member and the axial end surface of the rubber stopper portion on the outer cylindrical member side. Features.

  According to a second aspect of the present invention, in the first aspect, the interval between the circumferential end of the straight portion and the inner cylindrical member is wider than the interval between the circumferential end of the straight portion and the outer cylindrical member. It is characterized by being set.

  According to a third aspect of the present invention, in any one of the first and second aspects, the overflow hole for releasing excess rubber material from the injected rubber material is a molding cavity of the rubber stopper portion on the outer cylinder member side. And an overflow hole rubber projection formed by the overflow hole is left in the rubber stopper portion on the outer cylinder member side.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the injection hole rubber protrusion is positioned away from the outer peripheral surface of the inner cylinder member toward the outer cylinder member, and the shaft of the inner cylinder member As it progresses to the end side in the axial direction, it has a shape protruding in an oblique direction to be separated from the inner cylinder member to the outer cylinder member side.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the injection path is provided in a pair to inject the rubber material into a molding cavity of the rubber stopper portion on the pair of inner cylinder members side, The injection hole rubber protrusion is left in each of the rubber stopper portions on the inner cylinder member side.

Effects and effects of the invention

  As described above, the present invention arranges the injection path of the rubber material in the molding die so as to inject the rubber material into the molding cavity of the rubber stopper portion on the inner cylinder member side at the time of vulcanization molding of the rubber elastic body. The injection hole rubber projection formed at the injection hole at the end of the path is left in the rubber stopper part on the inner cylinder member side without leaving in the rubber main body part. Even if an input in a direction perpendicular to the axis or other directions is applied to the rubber main body, and the rubber main body is distorted or stressed, there is no injection hole rubber protrusion on the rubber main body. Stress concentration occurs, cracks are generated from the stress concentration, and the crack progresses further. This can solve the problem of reducing the durability life of the vibration-proof bushing.

  On the other hand, the rubber stopper on the side of the inner cylinder member is not a part where distortion or stress is always generated during vibration absorption, but is a part that only temporarily deforms when the stopper is operated. Even if exists, the problem that it becomes a big factor which reduces a durable life does not arise.

It should be noted that it is not conceivable to leave this injection hole rubber protrusion in the rubber stopper part on the outer cylinder member side, but in this way, the rubber material is injected into the rubber stopper part on the outer cylinder member side and from there If you try to rotate the rubber material into the molding cavities of the rubber main body part and the rubber stopper part on the inner cylinder member side, it will be difficult for the rubber material to fill the entire molding cavity evenly, and in some cases, there may be a lack of thickness. is there.
Therefore, it is preferable to use the molding cavity of the rubber stopper portion on the inner cylinder member side as the injection position of the rubber material.

In this case, it is desirable that the interval between the circumferential end of the straight portion and the inner cylindrical member is set wider than the interval between the circumferential end of the straight portion and the outer cylindrical member (claim 2).
When the rubber material is injected into the rubber stopper portion on the inner cylinder member side, more specifically, into the molding cavity, the injected rubber material passes through the gap formed between the circumferential end of the straight portion and the inner cylinder member. It flows out into the molding cavity of the rubber main body part, and further fills the molding cavity of the rubber stopper part on the outer cylinder member side while filling the molding cavity of the rubber main body part.

Thus, when the rubber material injected into the molding cavity of the rubber stopper portion on the inner cylinder member side flows out through the gap between the circumferential end of the straight portion and the inner cylinder member, frictional heat is generated there. Is produced. The calorific value increases as the gap becomes narrower.
Therefore, for example, when the temperature of the rubber material at the time of injection is 80 ° C., when the gap is extremely narrow, the rubber material may reach a high temperature such as 150 to 160 ° C. which is the vulcanization temperature in the process of passing through the gap. In this case, so-called burnt rubber may be produced in the course of the rubber material passing through the gap. Thus, when such burnt rubber is produced, the burnt rubber is mixed in the rubber body. When the vibration isolating bush is used, cracks are likely to be generated and progress from the location of the burnt rubber, which causes the durability of the vibration isolating bush to be reduced.

Therefore, in the present invention, the interval between the circumferential end of the straight portion and the inner cylinder member is set wider than the interval between the circumferential end and the outer cylinder member, and the rubber material passes when the rubber material is injected. It is desirable to ensure a wide gap.
By doing so, the amount of heat generated when the rubber material injected into the molding cavity of the rubber stopper portion on the inner cylinder member side flows out through the gap between the circumferential end of the straight portion and the inner cylinder member Therefore, it is possible to effectively prevent the occurrence of burnt rubber during the passage, and to effectively prevent the burnt rubber from being mixed into the rubber main body.
Thereby, it is possible to ensure good durability in the vibration-proof bushing.

In addition, as a result of widening the interval between the circumferential end portion of the straight portion and the inner cylinder member, the interval between the circumferential end portion and the outer cylinder member is inevitably narrow.
Accordingly, when the rubber material passes through the gap between the circumferential end of the straight portion and the outer cylinder member and flows into the molding cavity of the rubber stopper portion on the outer cylinder member side, the amount of heat generated there increases. There is a possibility that the burnt rubber is produced and mixed into the rubber stopper portion on the outer cylinder member side.
However, the rubber stopper portion on the outer cylinder member side, like the rubber stopper portion on the inner cylinder member side, is not a portion where distortion or stress is always generated during vibration absorption, but only temporarily deforms when the stopper is operated. Since it is a part, even if burnt rubber is mixed in the rubber stopper portion on the outer cylinder member side, there is no problem that this becomes a major factor that decreases the durability life of the vibration isolating bush.

  Here, the shape of the straight portion can be a shape in which the distance between the outer cylinder member and the inner cylinder member is the narrowest at the circumferential end.

In the present invention, an overflow hole for releasing surplus rubber material out of the injected rubber material is provided in the molding die in communication with the molding cavity of the rubber stopper portion on the outer cylinder member side, and the overflow hole The overflow hole rubber projections formed in step (2) can remain in the rubber stopper portion on the outer cylinder member side (claim 3).
As a result of leaving the injection hole rubber projection in the rubber stopper part on the inner cylinder member side and narrowing the interval between the circumferential end of the straight part and the outer cylinder member, the injected rubber material is on the inner cylinder member side. After filling the molding cavity of the rubber stopper part and the molding cavity of the rubber main body part, the molding cavity of the rubber stopper part on the outer cylinder member side is finally filled.

  In this case, if the rubber stopper portion on the outer cylinder member side is left with a rubber projection on the overflow hole, that is, the overflow hole is provided in the mold so as to communicate with the molding cavity of the rubber stopper portion on the outer cylinder member side. For example, the rubber material can be smoothly flowed in the molding cavity while air in the molding cavity is smoothly discharged through the overflow hole when the rubber material is injected, and each molding cavity can be filled with the rubber material well. Occurrence of defects such as lack of wall due to poor flow can be effectively prevented.

In this case, an overflow hole rubber projection remains on the rubber stopper portion on the outer cylinder member side.
For example, if an overflow hole is provided in communication with the molding cavity of the rubber body, and the overflow hole rubber protrusion remains in the rubber main body, the overflow hole rubber protrusion is connected to the vibration isolating bush in the same manner as the injection hole rubber protrusion. It becomes a factor which reduces durability.
However, as described above, the rubber stopper portion on the outer cylinder member side is not a part where distortion or stress is always generated during vibration absorption, and therefore, the overflow hole rubber protrusion remains on the rubber stopper portion on the outer cylinder member side. Even so, it is not a major factor that particularly reduces the durability of the vibration-proof bushing.

According to a fourth aspect of the present invention, the injection hole rubber protrusion is positioned away from the outer peripheral surface of the inner cylinder member toward the outer cylinder member, and protrudes obliquely with respect to the axial direction.
When the injection hole rubber protrusion (that is, the injection hole of the mold) is positioned away from the outer peripheral surface of the inner cylinder member in this way, the injection hole is positioned in contact with the outer peripheral surface of the inner cylinder member. As described above, the rubber material injected vigorously from the injection hole causes the adhesive applied to the outer peripheral surface of the inner cylinder member to flow together, and this does not cause the problem that the adhesive peeling occurs. A good adhesive force between the member and the rubber elastic body can be ensured.

Further, in this way, the injection hole, that is, the end of the injection path is positioned away from the outer peripheral surface of the inner cylinder member toward the outer cylinder member side, and further, the injection path is axially directed to the axial end (axial end) side of the inner cylinder member. Since it will extend obliquely so as to be separated to the outer cylinder member side as it goes to the step, the inner side of the injection path in the molding die, that is, the thickness of the inner cylinder member side portion can be secured thick, The required strength of the same part can be ensured.
Further, according to the fourth aspect, since the injection path extends obliquely toward the outer peripheral surface of the inner cylinder member, the rubber material injected into the molding cavity of the rubber stopper portion on the inner cylinder member side through the injection path Is smoothly flowed in the circumferential direction by the guide action of the outer peripheral surface of the inner cylinder member, and the rubber material is uniformly distributed in the molding cavity of the rubber body part and the rubber stopper part of the outer cylinder member side with a smooth flow. Can be made.

In the present invention, in order to inject the rubber material into the molding cavities of the rubber stopper portions on the pair of inner cylinder members, the above injection paths correspond to the molding cavities of the rubber stopper portions on the inner cylinder member side. A pair of injection hole rubber protrusions can be left on each of the rubber stoppers on the inner cylinder member side.
By doing so, the rubber material injected from the injection hole is more satisfactorily filled into the molding cavities of the rubber body portion connected to the whole, the rubber stopper portion on the inner cylinder member side, and the rubber stopper portion on the outer cylinder member side. become able to.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
1 and 2, reference numeral 10 denotes a vibration isolating bushing according to the present embodiment, which includes an inner cylinder fitting (rigid inner cylinder member) 12, an outer cylinder fitting (rigid outer cylinder member) 14, and an annular space between them. And a cylindrical rubber elastic body 16 is embedded.
The rubber elastic body 16 is integrally vulcanized and bonded to the inner cylinder fitting 12 and the outer cylinder fitting 14.
The rubber elastic body 16 is provided with a pair of straight portions (recesses) 18 on both side positions in the direction perpendicular to the axis with the inner cylinder fitting 12 interposed therebetween.
As shown in FIGS. 3A and 4, these straight portions 18 have a form that penetrates the rubber elastic body 16 in the axial direction.

Each of the straight portions 18 has a slit-shaped portion 18-1 having an arc shape and enlarged hole portions 18-2 at both ends in the circumferential direction.
Here, the upper portion 18 and the lower portion 18 are symmetrical in the vertical direction in the drawing. That is, it is symmetrical in the vertical direction with respect to a line Q perpendicular to the center line P passing through the center O of the inner cylinder fitting 12.
Each of the pair of straight portions 18 has a symmetrical shape on the left and right in the drawing with respect to the center O of the inner cylinder fitting 12 and the center line P passing through the center of the straight portion 18.

As shown in FIG. 3B, the rubber elastic body 16 is connected to the inner cylinder fitting 12 and the outer cylinder fitting 14 at a circumferential position between the pair of straight portions 18 and 18, respectively. A rubber stopper portion 22 on the inner cylinder fitting 12 side and a rubber stopper portion 24 on the outer cylinder fitting 14 side facing each other in the direction perpendicular to the axis with the straight portions 18 interposed therebetween. Each pair has.
The rubber stopper portion 22 on the inner cylinder fitting 12 side has a stopper surface 22-1 having an arc shape and a flat surface along the circumferential direction.
On the other hand, the rubber stopper portion 24 on the outer cylinder fitting 14 side has an uneven surface having a generally arcuate and wavy shape on the stopper surface 24-1.
Here, the pair of rubber main body portions 20 and the pair of rubber stopper portions 22 and 24 are integrally formed continuously.

Reference numeral 26 denotes a positioning portion that protrudes from the upper surface of the rubber stopper portion 22 on the inner cylinder fitting 12 side at a position 180 ° apart in the circumferential direction. This positioning portion 26 is positioned when the vibration isolating bush 10 is assembled. It is a part.
Specifically, the vibration isolating bushing 10 of the present embodiment is assembled by being axially press-fitted into the mating cylindrical press-fitting portion of the outer cylinder fitting 14, and in that case the circumferential assembling position is required. Positioning is performed by the positioning unit 26.
Specifically, the position of the vibration isolating bush 10 in the circumferential direction relative to the press-fitting jig can be defined by fitting the positioning portion 26 into a concave portion having a corresponding shape of the press-fitting jig. Thus, the vibration isolating bush 10 can be assembled in a state where the position in the circumferential direction is determined with respect to the mating press fit portion by press fitting the vibration isolating bush 10 into the press fitting portion on the mating side.
These protruding positioning portions 26 are located on a center line P passing through the center O of the inner cylinder fitting 12 as shown in FIG.

Reference numeral 28 denotes an injection hole rubber projection formed by an injection hole 48 at the end of an injection path 46 formed in a molding die 30 (see FIG. 5) described later when the rubber elastic body 16 is vulcanized. Then, these injection hole rubber protrusions 28 are positioned in the rubber stopper portions 22 on the pair of inner cylinder fittings 12 side, respectively.
Here, these injection hole rubber protrusions 28 are located at positions spaced from the outer peripheral surface of the inner cylinder fitting 12 toward the outer cylinder fitting 14 as clearly shown in FIGS. The positioning portions 26 are positioned on the same side of the positioning unit 26 on the right side in the figure with a predetermined interval.
That is, the pair of injection hole rubber protrusions 28 are located at positions that are offset from the center line P to the same side in the circumferential direction, and at positions that are offset from the center in the circumferential direction of the straight portion 18 to the right end side in each figure. ing.

In the present embodiment, as shown in FIG. 2, each circumferential end of the pair of straight portions 18, that is, each of the enlarged hole portions 18-2 at the right end portion and the left end portion in the drawing and the outer tube fitting 14. The interval between them is the same interval A, and similarly, the interval between the inner cylindrical fitting 12 is the same interval B.
Thus, here, the interval B is set wider than the interval A.
The interval A is desirably 1 mm or less. Specifically, the interval A is 0.5 mm here.

In FIG. 2, 29 is an overflow hole rubber projection formed by an overflow hole provided in the molding die 30 described later and remaining in the rubber stopper portion 24 on the outer cylinder fitting 14 side.
The overflow hole rubber protrusion 29 is formed on each of the rubber stopper portions 24 on the pair of outer cylinder fittings 14 side.
Here, each of the overflow hole rubber protrusions 29 is located on the opposite side to the corresponding injection hole rubber protrusion 28 with respect to the center line P.

In FIG. 5, reference numeral 30 denotes a molding die for vulcanization molding of the vibration-proof bushing 10, and has split dies 32, 34, and 36 that are divided in the vertical direction in the same figure, and a pair of core dies 38 and 40. is doing.
Reference numerals 42 and 44 denote molding cavities for molding the rubber stopper portion 22 on the inner cylinder fitting 12 side and the rubber stopper portion 24 on the outer cylinder fitting 14 side formed on the molding die 30, respectively. An injection path 46 of rubber material is formed in the mold 30 so as to communicate with the mold 30. In the figure, reference numeral 48 denotes an injection hole at the end of the injection path 46.
As shown in the figure, the injection path 46 positions the terminal injection hole 48 at a position separated from the outer peripheral surface of the inner cylinder fitting 12 toward the outer cylinder member 14, and advances in the axial direction toward the axial end side of the inner cylinder fitting 12. As it extends obliquely outward in the direction perpendicular to the axis.
That is, the injection path 46 is provided so as to be inclined obliquely with respect to the axial direction toward the outer peripheral surface of the inner cylinder fitting 12.

In this embodiment, when the rubber elastic body 16 is vulcanized, a rubber material is first injected into the molding cavity 42 for molding the rubber stopper portion 22 on the inner cylinder fitting 12 side through the injection path 46.
The rubber material injected into the molding cavity 42 fills the molding cavity 42, and then the gap between the circumferential end portion of the straight portion 18 and the inner cylindrical metal fitting 12 (represented by the interval B in FIG. 2). Between the circumferential end of the straight portion 18 and the outer tube fitting 14 while filling the molding cavity (not shown) of the pair of rubber main body portions 20 and filling them. 2 passes through the molding cavity 44 of the rubber stopper portion 24 on the outer cylinder fitting 14 side, and fills the molding cavity 44.

Excess rubber material overflows from the molding cavity 44 through an overflow hole (not shown) of the molding die 30 provided at the position of the overflow hole rubber projection 29 in FIG.
At this time, the air pushed along with the flow of the rubber material in the molding cavity 44 is finally driven into the position of the overflow hole, and is then smoothly discharged out of the molding cavity 44 from the overflow hole.
After each molding cavity is filled with the rubber material, the injected rubber material is vulcanized by holding the rubber material in a pressurized and heated state for a certain period of time, and at the same time, the inner cylinder fitting 12 and the outer cylinder fitting 14 are applied. On the other hand, it is vulcanized and bonded together.

Thereafter, the mold 30 is disassembled, and the integrally vulcanized product, that is, the vibration isolating bush 10 is taken out from the mold 30.
At this time, the rubber elastic body solidified in the injection path 46 is divided at the constricted portion 50 formed in the injection path 46 when the molding die 30 is disassembled, and is solidified in the injection hole 48, that is, the injection hole rubber formed in the injection hole 48. The protrusions 28 are left on the rubber elastic body 16 side, specifically, the rubber stopper portion 22 on the inner cylinder fitting 12 side.
Further, the overflow hole rubber protrusion 29 formed by the overflow hole of the mold 30 remains in the rubber stopper portion 24 on the outer cylinder fitting 14 side.
The injection hole rubber protrusion 28 and the overflow hole rubber protrusion 29 in FIG. 2 remain in the rubber stopper portions 22 and 24 in this way.
As clearly shown in FIG. 4, the injection hole rubber protrusion 28 is formed so as to protrude obliquely outward with respect to the axial direction of the inner cylinder fitting 12 in accordance with the inclination of the injection path 46. Yes.

In the anti-vibration bushing 10 of the present embodiment as described above, even if inputs in the twisting direction, the direction perpendicular to the axis and other various directions are applied to the rubber main body portion 20 and the rubber main body portion 20 is distorted or stressed, Since the injection hole rubber protrusion 28 does not exist in the rubber main body portion 20, stress concentration occurs at the root of the rubber main body portion 20, cracks are generated from the root, and the durability of the anti-vibration bush 10 decreases due to further progress. Does not occur.
On the other hand, the rubber stopper portion 22 on the inner cylindrical metal fitting 12 side is not a portion where distortion or stress is always generated during vibration absorption, but is a portion that only temporarily deforms when the stopper is operated. Even if the rubber protrusions 28 are present, this does not become a major factor for reducing the durability life.

  In the present embodiment, the injection hole rubber protrusion 28 is not left on the rubber stopper portion 24 on the outer cylinder fitting 14 side but on the rubber stopper portion 22 on the inner cylinder fitting 12 side, that is, on the inner cylinder fitting 12 side. Since the rubber material is rotated to the molding cavities of the rubber main body 20 and the rubber stopper 24 on the outer cylinder fitting 14 side through the molding cavities 42 of the rubber stopper 22, the injected rubber material is smoothly molded into each molding. The rubber elastic body 16 which is wrapped around and filled in the cavity and connected to one is well molded.

Here, in the present embodiment, the interval B between the circumferential end portion (enlarged hole portion 18-2) of the straight portion 18 and the inner cylinder member 12 is wider than the interval A between the circumferential end portion and the outer cylinder member 14. Since the clearance through which the rubber material passes is set wide, the rubber material injected into the molding cavity 42 of the rubber stopper portion 22 on the inner cylinder member 12 side is separated from the circumferential end of the straight portion 18. The amount of heat generated when flowing out through the gap between the inner cylindrical members 12 can be reduced, and it is possible to effectively prevent the occurrence of burnt rubber during the passage, and the burnt rubber is mixed into the rubber body 20. It can be effectively prevented.
As a result, good durability in the vibration-proof bushing 10 can be ensured.

  In addition, as a result of widening the interval B between the circumferential end of the straight portion 18 and the inner cylinder member 12, the interval A between the circumferential end and the outer cylinder member 14 is inevitably narrow. The rubber stopper portion 24 on the member 14 side, like the rubber stopper portion 22 on the inner cylinder member 12 side, is not a portion where distortion or stress is always generated during vibration absorption, but only temporary deformation during the stopper operation. Since this is a part, a large amount of heat is generated when the rubber material flows into the molding cavity 44 of the rubber stopper portion 24 through the gap between the circumferential end portion of the straight portion 18 and the outer cylinder member 14, and is burned accordingly. Even if rubber is mixed into the rubber stopper portion 24, this does not become a major factor for reducing the durability life of the vibration isolating bush 10.

In the present embodiment, it is desirable that the straight portion 18 be provided on the outer peripheral side as much as possible in order to suppress heat generation when the injected rubber material passes through the portion of the interval B with the interval B of FIG. However, the following advantages can be obtained by providing the straight portion 18 on the outer peripheral side as much as possible.
That is, when the interval A is relatively narrow, the final filling portion of the injected rubber material becomes the molding cavity 44 of the rubber stopper portion 24 on the outer cylinder fitting 14 side, and the position of the final joining portion of the rubber material is It is possible to define the molding cavity 44 of the rubber stopper portion 24, and further, it is possible to define the final air entry position in the molding cavity 44. Then, by providing an overflow hole in that portion, excess rubber material can be smoothly discharged from the molding cavity 44 together with air.

In addition, by providing the curled portion 18 at the position on the outer peripheral side as much as possible, it is possible to effectively avoid deterioration in durability due to crack generation and progression at the circumferential end portion of the curled portion 18 when the vibration isolating bush 10 is used. .
If the curled portion 18 is provided at a position on the inner peripheral side close to the inner cylindrical metal member 12, a large distortion is caused at the circumferential end of the curled portion 18 when the inner cylindrical metal member 12 is displaced relative to the outer cylindrical metal member 14. However, it is possible to reduce the distortion generated at the circumferential end of the straight portion 18 as much as possible by providing the straight portion 18 on the outer peripheral side as much as possible. Durability can be enhanced by suppressing the occurrence of cracks at the circumferential end of the portion 18.
In the present embodiment, the reason why the distance A is set to an extremely small value of 0.5 mm is based on such a reason.

  In this case, if the injection hole rubber protrusion 28 is left in the rubber stopper portion 24 on the outer cylinder fitting 14 side, the portion of the rubber material injected into the molding cavity 44 of the rubber stopper portion 24 represented by the interval A (narrow) A large amount of heat is generated when the gas passes through the gap) and flows into the molding cavity of the rubber main body portion 20 to raise the temperature of the rubber material and easily produce burnt rubber. However, according to this embodiment, such a problem is avoided. be able to.

  In this embodiment, the overflow hole rubber protrusion 29 is left on the rubber stopper portion 24 on the outer cylinder member 14 side. However, the rubber stopper portion 24 on the outer cylinder member 14 side is always subjected to distortion and stress during vibration absorption. Therefore, even if the overflow hole protrusion 29 remains in the rubber stopper portion 24 on the outer cylinder member 14 side, the durability of the vibration isolating bush 10 is not particularly deteriorated.

  Further, in the present embodiment, the injection path 46 is provided so that the terminal injection hole 48 is positioned away from the outer peripheral surface of the inner cylinder member 12 toward the outer cylinder member 14, and the injection path 46 is provided in the inner cylinder member 12. Since the injection hole 48 is provided so as to extend obliquely with respect to the axial direction toward the outer peripheral surface of the inner cylindrical member 12, the injection hole 48 is vigorously injected from the injection hole 48 as in the case where the injection hole 48 is positioned in contact with the outer peripheral surface of the inner cylinder member 12. The adhesive material applied to the outer peripheral surface of the inner cylinder member 12 flows together with the rubber material, and this does not cause a problem that the adhesive peeling occurs, and the inner cylinder member 12 and the rubber elastic body 16 are good. A sufficient adhesive force can be secured.

  Further, in this way, the injection hole 48, that is, the end of the injection path 46 is positioned away from the outer peripheral surface of the inner cylinder member 12 toward the outer cylinder member 14, and the injection path 46 is axially directed to the axial end side of the inner cylinder member 12. Since it extends obliquely outward in the direction perpendicular to the axis as it proceeds to, the thickness (T (see FIG. 5)) of the portion on the inner cylinder member 12 side, that is, the inner cylinder member 12 side, is ensured to be thicker. The required strength of the same part can be ensured.

  Moreover, in this embodiment, since the injection path 46 is inclined and the rubber material from the injection path 46 is injected obliquely toward the outer peripheral surface of the inner cylinder fitting 12, the guiding action of the outer circumference of the inner cylinder fitting 12 is achieved. The rubber material can smoothly flow in the circumferential direction and can be filled in each molding cavity.

  Further, in the present embodiment, the injection hole rubber projections 28 are left in the rubber stopper portions 22 on the inner cylinder fitting 12 side, that is, in each of the pair of molding cavities 42 for molding the rubber stopper portion 22. Since the rubber material is injected, the rubber material can be more satisfactorily filled into the molding cavities, and the molding can be performed better.

  Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be applied to a liquid seal type vibration-proof bushing in which a liquid is sealed in a liquid chamber. It can be configured in variously modified forms within a range that does not.

It is a perspective view of the vibration proof bush of one Embodiment of this invention. It is a front view of the vibration isolating bush of the same embodiment. (A) It is an AA sectional view in FIG. (B) It is the II sectional drawing in FIG. FIG. 3 is a cross-sectional view of Wu in FIG. It is a figure which shows the shaping | molding die of the vibration isolating bush of the embodiment. It is a figure which shows an example of the conventional anti-vibration bush.

Explanation of symbols

10 Anti-vibration bush 12 Inner cylinder fitting (inner cylinder member)
14 Outer cylinder fitting (outer cylinder member)
16 Rubber elastic body 18 Straight part 20 Rubber main body part 22, 24 Rubber stopper part 28 Injection hole rubber protrusion 29 Overflow hole rubber protrusion 30 Mold 42, 44 Mold cavity 46 Injection path 48 Injection hole

Claims (5)

A rigid inner cylinder member and an outer cylinder member, and a rubber elastic body disposed between the inner cylinder member and the outer cylinder member. The rubber elastic body has a direction perpendicular to the axis across the inner cylinder member. And a pair of straight portions penetrating the rubber elastic body in the axial direction at both side positions of the inner cylindrical member and the inner cylindrical member and the outer cylindrical member at the circumferential positions between the straight portion and the straight portion. A pair of rubber main body portions connected in a right angle direction, and a pair of rubber stopper portions on the inner cylinder member side and rubber stopper portions on the outer cylinder member side facing each other in the direction perpendicular to the axis with the straight portion interposed therebetween In the anti-vibration bushing that is provided in a continuous form with the same rubber material,
During the vulcanization molding of the rubber elastic body, the rubber material is injected into the molding cavity of the rubber stopper portion on the inner cylinder member side, and the rubber is put into each molding cavity of the rubber main body portion and the rubber stopper portion on the outer cylinder member side. The injection path of the rubber material in the mold is arranged so as to rotate the material , and the injection hole rubber projection formed by the injection hole at the end of the injection path is inserted into the rubber main body part and the rubber stopper part on the outer cylinder member side. without leaving the leave the rubber stopper of the inner cylinder member, and the rubber stopper of the inner cylinder member side end surface in the axial direction, the rubber axial end face and the outer cylinder member side of the outer cylinder member An anti-vibration bush characterized by being spaced apart from the axial end surface of the inner cylinder member toward the axial center side at a larger interval than the interval between the stopper portion and the axial end surface .   In Claim 1, The space | interval between the circumferential direction edge part of the said curl part and the said inner cylinder member is set widely with respect to the space | interval between the circumferential direction edge part of the said curb part, and the said outer cylinder member. Anti-vibration bush.   3. The molding die according to claim 1, wherein an overflow hole for releasing surplus rubber material of the injected rubber material communicates with a molding cavity of a rubber stopper portion on the outer cylinder member side. An anti-vibration bush characterized in that an overflow hole rubber projection formed by the overflow hole is left on the rubber stopper portion on the outer cylinder member side.   4. The injection hole rubber protrusion according to claim 1, wherein the injection hole rubber protrusion is positioned away from the outer peripheral surface of the inner cylinder member toward the outer cylinder member, and advances in the axial direction toward the shaft end side of the inner cylinder member. Accordingly, the anti-vibration bushing has a shape protruding in an oblique direction away from the inner cylinder member toward the outer cylinder member side.   5. The rubber according to claim 1, wherein a pair of the injection paths are provided to inject the rubber material into a molding cavity of the rubber stopper portion on the pair of inner cylinder members. An anti-vibration bush characterized in that the injection hole rubber protrusion is left on each of the stopper portions.

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